The present invention relates to a small-format zoom optical system having improved imaging capabilities, and an imaging apparatus incorporating the same.
In recent years, a bifocal changeover type imaging lens has been proposed for a small-format zoom imaging lens having fewer driving mechanisms (see JP(A) 2007-93961). The optical system set forth in Patent Publication 1 comprises three groups of negative/positive/positive profile, and is designed to implement zooming by moving only the second lens group in the optical axis direction. And unlike a commonly used zoom lens, what is required there is only to satisfy bifocal imaging capabilities at the wide-angle end and telephoto ends so that during zooming the first and third lens groups can remain fixed, making it possible to simplify the mechanism involved.